Raven Coves quest help - important

[lerzba]

I'm at "Get the Last Idol" part, 82% done with the whole quest.

It says I have to kill 4 ghosts at the same time on the southern idol, I tracked it and tried killing them with my mate that kept healing me and helped hiself a few times, everytime I kill ALL of the ghosts,It still says there are ghosts surrounding the idol and I can't loot it.

I been here for 2 hours trying to figure it out.. I went and made ally traitors follow me, but same thing, it just wont work!!

Can someone reply quick, what I am doing wrong!!